Tuning mechanism for radio receivers and the like



March 20,1945. M, MCGARVEY 2,372,099

TUNING MECHANISM FOR RADIO RECEIVERS AND LIKE Filed Aug. 3, 1940 6 Sheets-Sheet l INVENTOR ATTORNEY March 20, 1945. H. J. M GARVEY 2,372,099

TUNING MECHANISM FOR RADIO RECEIVERS AND THE LIKE Fil ed Aug. 3. 1940 6 Sheets-Sheet 2 ATTORNEY March 20, 1945. L MOGARVEY 2,372,099

TUNING MECHANISM FOR RADIO RECEIVERS AND THE LIKE Filed Aug. 3, 1940 6 Sheets-Sheet 5 7d a I a March 20, 1945. H. MCGARVEY 2,372,099

TUNING MECHANISM FOR RADIO RECEIVERS AND THE LIKE Filed Aug. 3, 1940 6 Sheets-Sheet 4 ATTORNEY March 20, 1945. H. J. M GARVEY 2,372,099

TUNING MECHANISM FOR RADIO RECEIVERS AND LIKE Filed Aug. 3, 1940 6 Sheets-Sheet 5 H V MM m TGZN 31% T Ml 0 a MYM HB a 3,

March 20, 1945.

H. J. MCGARVEYY .TUNING MECHANISM FOR RADIO RECEIVERS AND THE LIKE Filed Aug. 3, 1940 6 Sheets-Sheet 6 a o a Z 5 INVENTQR f/ARQAQ f/Vc GAAVE).

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ATTORNEY Patented Mar. 20, 1945 UNITED STATES 1 PATENT OFFICE TUNING MECHANISM FOR RADIO RECEIVERS AND THE LIKE Harold J. McGarvey, Bnlhlo, N. 1., assiznor to I Colonial Radio Corporation, Buflalo, N. Y.

Application mm s, 1940, Serial No. 350,420

4 Claims. 01. 14-10) "This invention relates to tuning mechanisms to means by which the radio receiver may be quickly and accurately tuned to a particular station for which the apparatus has previously been set or calibrated. In the particular embodiment herein disclosed, the tuning mechanism is 01' the so-called electrically operated push button type, by means of which the operator may push a button' and the apparatus will be electrically adiusted to the particular station for which that push button has been set or calibrated.

My apparatus also contemplates manual means for selecting the desired stationswhich may be operated independently of and without interference with the push buttons, and for this, there is interposed between the manual drive and the tuning element per se a clutch which operates to disconnect the manual control selector mechanism from the tuning apparatus when any push button is operated. Immediately after the operation of the push button, the clutch is again connected so that the apparatus may be tuned manually.

While I have shown and described my apparatus as embodying a so-called gang condenser for this purpose, it will be understood that my invention is applicable to receivers which are tuned by other means, for example by the variation of inductance.

Among the objects of my invention may be mentioned:

To provide apparatus which is relatively simple and economical to manufacture consisting practically entirely of punch press and screw machine parts, involving a minimum of material and requiring a minimum of labor in assembly;

To provide electrically actuated apparatus which may be operated with very little current drain, particularly adapted ior use on. automobiles, boats and the like, where it may be operated irom the storage battery usually provided for -buttclmmayheeasilyandquiclrlypre-setorcalibratedwithouttheuseoftooisflhatmtomltn provide: apparatus in which the calibration of particular buttons to particular trequencies may be easily and quickly made without tools and without requiring the disassembly of the set, or removal of buttons, cover plates, or other parts, and in which the buttons may be re-calibrated whenever desired in a similar manner.

To provide apparatus in which the manual knob drive may be disconnected from the tuning shaft whenever any push button is operated;

To provide such apparatus in which the normal operation of the buttons to. select stations can not accidentally disturb the calibrations previously made;

To provide such apparatus in which the selection of a previously calibrated station may be achieved by simply pushing the button in and in which re-calibration of the button may be achieved simply by pulling the button out and rotating it;

, To provide such apparatus in which rotation ofthe button in any but the calibrating position will not disturb the calibration already made.

Still other objects and advantages of my invention will be apparent from the specification.

2B In this application I have particularly pointed out and distinctly claimed the.part,improvement or combination which I claim. as my invention or discovery and I have explained the principles thereof and the best mode in which I have contemplated applying those principles, so as to distinguish my inventionrum other inventions.

In the drawings:

Fig. 1 is a front elevation view of a radio receiver according to my invention;

Fig. 2. is a bottom plan view partly in section and partly broken away thereof;

Fig. 3 is a partial mctional elevation on lines 1-4 0! Fig. 2

Fig. i is a similar view on lines 4- of Fig. 2

l'lg.5isasimilarview.onlinesI--Iotfig.2,

the mechanism beingin an intermediate position in process of selecting a station;

Pig.6isaviewonthes1melinesas1'lx.5,but

showingthemechanisrrrinilnalpositioninselecting a station;

Fig. '1 is a view on the same lines asxFig. 5,, but showing the mechanism in position to calibrate a button;

so rmaaatopplmm uuymsecumz' Fig. 12 is a top plan view partly in section of still another modification: and

Fig. 13 is a section on lines |3-|3 of Fig. 12.

Referring now more particularly to Fig, 1, designates the casing or container of the radio receiver. which may have manual rotary knobs 2 and 3 positioned on opposite sides of the front face thereof, 2, designating the knob which may operate the on-ofl' switch and volume control, and 3 the knob operating the tuning mechanism manually to carry the pointer 4 across the dial 4a, 5, 6, I, 8, 9 and III may represent the push buttons, which may be calibrated or pre-set so that when a particular button-is pushed, a particular station is tuned in as indicated by the station call letter tabs.

The actual syntonizing of the circuit may be done by any suitable means, such for instance as the variable gang condenser having a series of stators into and out of which rotors may swing about axis I2. Such condensers are well-known in the art, and since the particular condenser construction per se is not a part of this invention, the same is not described in detail. It will be understood that other tuning instrumentalities, such as variometers or the like my be employed in place of or in addition to the variable condenser shown.

In selecting a station manually by means of knob 3, rotation of the knob 3 rotates the shaft l5 (see Fig. 3) which may be a flexible shaft connected to knob 3 whichln turn rotates worm I8, this worm l6 engaging a gear I! which is normally connected to a second gear l8 through the medium of a clutch which will be described hereafter more in detail. Ordinarily, the clutch directly connects gear I! to gear i8 so that gear l8 rotates with gear I! at the same speed. Gear I8 may engage a gear l9 mounted on the stud shaft |2a of the variable condenser and a pulley may also be mounted on stud shaft i211, the pulley carrying cord 2| which in any suitable and well-known manner carries the pointer 4 across the dial. Thus, rotating knob 3 normally rotates condenser H and tunes the receiver.

Pushing any of the buttons 5 to ID forward, first causes closure of switch 22 in a manner which will be described hereafter. Closure of switch 22 serves to energize the solenoid 23 which then draws in its core 24. Connected to the core 24 there is provided a rod 25 mounted in a cradle or bail 26 pivoted at 26a so that when 24 moves into the coil, the cradle or ball is swung downwardlyas seen in Fig. 2, counter-clockwise, as in Figs. 5 and 6.

Corresponding to each of the push buttons 640 inclusive, there may be provided a plunger 30,. 3|, 32, 33 and 34 respectively althoughfor simplicity of illustration some of these have been omitted from the drawings. The plungers may be spring biased to forward position, as by springs a, 3|a, etc., and are selectively driven by the forward motion of the cradle.

For this purpose the cradle carries a pivoted latch for each plunger, the latches being 40, 4|, 42, 43, and 44 and these latches are mounted on the cradle in such a manner that they may be rocked counter-clockwise in the cradle through a small angle, but are normally biased to full clockwise position. When in the latter position they clear the plungers and the cradle may swing without moving any plungers. However, when a button is pressed, at the same time that the solenoid is energized, the corresponding latch is tipped counter-clockwise by mechanism which will be described later, into such a position that when the cradle swings, the right hand end of the latch engages a notch N on the lower face of its corresponding plunger and moves the said plunger to the full length of its downward motion in Fig. 2 (to the right in Figs. 5 and 6) When any plunger is moved to the full extent of its movement, it engages the tilt bar 58 and turns it to a greater or less extent, the amount of the turning being dependent upon the angular position of the contact-making sectors 60, iii, 62, 63 and 64 located on the plungers 30, 3|, 32, 83 and 34 respectively. This sector and tilt bar engagement and the resultantrotation of the tilt bar is best seen in Figs. 5 and 6, in which sector BI is shown pivotally mounted upon the end of its corresponding plunger 3| and normally secured against rotation. When the plunger 3| moves to the right in Fig. 5, it will be seen that the sector will strike one or the other of the faces SI and 52 of the tilt bar, and the tilt bar will be turned so that said faces are in alignment with the edge of the sector as shown in Fig. 6.

Since the tilt bar shaft is the rotor shaft, rotation of the tilt bar will rotate the condenser rotors, and for any particular position of the condenser corresponding to any particular wave length or frequency, there is a corresponding angular position of the tilt bar and also a corresponding angular position of the sector. Once .any particular sector has been rotated to the proper angular position corresponding to the desired station and secured in such position, repeated operation of its particular push button will always cause the tilt bar to return to the proper position to set the condenser for that particular station.

In apparatus of this general nature, it has heretofore been necessary to use special tools, and sometimes disassemble the receiver at least partially in order to adjust the various sectors in order to calibrate the receiver for particular stations. According to this invention, it is possible to adjust or calibrate any button without the use of any tools and without disassembling or partially disassembling the apparatus in any way. This is accomplished by providing gear teeth on the arcuate face of the sector, the gear teeth being respectively indicated at 10, l I, 12, 13, and 14. The gear teeth of each respective sector are engaged by a corresponding worm 83, 3|, 82, 83, and 34 respectively, mounted on the corresponding plungerand each worm may be driven by a corresponding flexible shaft 30, 9|, 32, 93 and 94, mounted on its particular plunger and extending forwardly beyond the end of the plunger into its particular button assembly as best seen in Figs. '1 and 8.

Each of these flexible shaft terminates in a small spline I00 to I34 and the splined end of the shaft projects into the rear end of the push button itself which is hollow. The rear end of each button is provided with an .internal spline ||0-| l4 to engage the spline upon the end of the flexible shaft. Normally the splines I00 and iii! are disengaged, and sufllcient clearance is provided so that the button may be rotated without rotating shaft 3|, but when the button is pulled out, the splines engage and rotation of the button rotates shaft 3|, worm 8| and sector 1|.

It will now be understood that in order to preset or calibrate any particular push button to a particular station it is only necessary to grasp the button desired and pull it out until the internal spline on the inner end of the button engages asraooe 1 or neutral position, the solenoid switch is closed and the plunger is held in position with the sector the tilt bar. Now by rotation of the button, the flexible shaft from the button to the sector is rotated and the sector is rotated through the action of its worm, thus rotating the tilt bar and changing the inning of the set. In order to select the desired station, one need only to continue to rotate the button until the desired station is heard at its best position, whereupon the button is pushed back to neutral position, the solenoid switch 'opens and all apparatus returns to neutral position except the sector which remains in the position to which it was turned by the operating of its worm. and the condenser, which remains in the angular position to which ing out of adjustment, the worm may be spring loaded as indicated at ill to I24, this spring loading serving to prevent any play between the worm notch on its corresponding plunger and then and gear and thereby holding the sector firmly ,in adjusted position. The pitch of the worm is preferably made such that the worm and gear connection is irreversible, the worm acting a a buttons to neutral position, best seen in Fig. '8.

The rearwardly extending portion of the button is preferably provided with a V-shaped circumferential :groove 1d. Normally resting in this groove .in the upper side thereof is the switch actuating bar I which is in the form of a bail pivoted about a horizontal axis forwarder switch '12, :may be under the movable switch contact no of solenoid 122. This switch actuating bar extends across :all of the buttons and normally lies within the vgroove in each button (so that upon movement of any push button, either in or out, the switch will be displaced and the solenoid switch will be closed. providing for the enerig'izing of the solenoid either when the button is pushed in to select a station or pulled out to change the calibration of the button.

For the of tannins the latch when a is moved, each button is preferably provided with a fill to 1|, pivotally mounted at its outer end as at l li a on housing,

just under buttomiand having a projection on its upp r side Ill") riding in the groove in The rear end of the linger backwardly and normally lies above its ng as will be seen more clearly in '4. the button is either pushed in 1 or pulled out, the movement of the button carries the 'V-shaped groove to 'one side or the other o projection on the liner, and the linger is accordingly tilted and engages its corhtchandswingsthesamecounter-- may be positioned within the housing to bias the V clockwiseaswillbeseeninl lmfi. Wbenthe cradiebeginstoswing,thelatchiirstengascsthe passes out of engagement with the finger, but the latch is prevented from falling back to initial position by its engagement with the undercut notch N in the plunger, and the latch will not return to initial position until the solenoid switch is de-energiaed and the cradle returned to initial position.

It has already been stated that I preferably provide a clutch interposed between the manual tuning means and the condenser shaft. A preferred manner of constructing the clutch mechanism will now be explained, and is best seen in Figs. 9 and 10. Referring to Figs. 3 and 4, it has been stated that rotation oi the manual tuning knob drives worm I. through shaft 15, the worm li engaging and rotating gear l1. Gear i! may be secured'to bushing ill suitably mounted on condenser shaft 12 free to rotate, but fixed axially by collars 202 and I". Sleeve 2" also carries at one extremity the clutch disc ill, consisting preferably 01 a thin sheet metal discl Discs Ill, sleeve "I and gear H are all rigidly secured together in a manner to rotate as a unit, but are free to rotate-with respect to the condenser shaft. Secured to condenser shaft I! to rotate therewith, there is preferably provided sleeve or collar 2" mentioned above, ca ryi g at its inner side gear II which engages gear is al ready described for the purpose of moving the dial indicator. Mounted on gear II and extending radially outward therefrom. I may provide an arm 201 terminating at its outer extremity in an oifset portion ill to which there may be secured as by rivet 2|! the pinch bar ill having its inner end terminating in a collar surrounding the shaft l2 and slightly oifset as at II I.

The arm I" and bar 2" and the disc Ill form the actual clutch itself. Bar III is biased by its own inherent resiliency away from disc ill and when permitted to take such position. there is suflicient clearance to permit the periphery of gisc 2" to pass between am 201 and pinch bar however, the lower end or pinch bar Ill is pressed in the direction of sleeve Ill, it will be seen that the periphery of disc III will be pinched between arm "rand pinch bar ill and that rotation of the disc Ill by connection through sleeve 2" and gear I! 'to the driving knob will cause rotation of sleeve 2" and thereby of the con denser shaft l2 and the condenser.

Normally this snitch mechanism is maintained in engaged position by rod 212 having its outer end bifurcated as at 212a and 2b, the bifurcated and passing between sleeve 2" and pinch bar Ill, The outer end of the bifurcated portion may be split .and slightly oitset or bent as at Iii, so that when rod 212 isbiased to its normal or rest position as by spring 2120, the wedging action of rod 2!! serves to hold the pinch bar Ill against arm 2|! and thereby clamp the periphery of disc 2", keeping clutch engaged. The forward end of rod 2|! is connected in any suitable manner and preferably by a slot adjustment providing for a certain amount of tolerance in setting up the apparatus) to rod 25 which is carlied on bail It; thus when any push button is operated and the solenoid switch closed as al ready described. the bail moves downwardly, as beeninligdpnshingrod 2i: downwardlyinthat ilgure, releasingthepressure on pinch bar III already described to the condenser shaft at a point beyond the clutch mechanism; that is to say, at a point between the clutch mechanism and the condenser, so that operation of the clutch mechanism does not interfere with operation of the dial and pointer, which is always connected to the condenser shaft itself and must move with any movement of the condenser shaft.

The modified forms of apparatus shown in Figs.

10 and 11 and 12 and 13 respectively differ very little from the form shown in Figs. 1-9 and the difference principally is that in the apparatus of Figs. 10 and 11, the worm and gear drive from the individual push buttons to the corresponding sector has been eliminated, this difierence resulting in mechanism which while not as conveniently adjustable for calibrating as the previously described form is possibly somewhat less expensive to manufacture.

In this modification, which electrically operated by means of the solenoid and ball as before, the plungers C, 25F, 252, 253, and 254 are provided with a pair of laterally extending ears, one behind the other, 258a, 2501), 25in, 25lb, etc., and one or both of the front and back ears on each plunger may be threaded to receive bolts 250e, 25lc, etc. fhe sectors 60, 6|, etc., in this instance do not need to be provided with gear teeth around their periphery, but each is held by means of a clamp strip 250d, 25ld, etc., which may take the form of a small disc slightly bent, as indicated and having a slot therein to receive the respective ear 250b, 25lb, etc., when the respective bolts 250e, life, etc., are retracted. The head of the respective bolts may extend through openings 250e, 25le, etc., in the front of the casing and may be covered by an escutcheon plate which may be removable for the purpose of callbrating the particular buttons.

- This may be done by flrst tuning the desired station by the manual tuning knob, then backing oil on the clamping bolt for the particular button, then operating that button, which will rotate the sector to the angular position which the tilt bar then has the sector being free to. turn, and, then while still holding the button in depressed posi-- tion, tightening the clamp bolt to clamp the sector in position. Another difference which may be pointed out is that since the push buttons do not need to be rotated, a very simple plunger structure in the form of a flat stamping may be utilized for each button, as indicated by reference numeral 300. As before, depressing any of the push buttons closes the solenoid switch 22 and rotates the corresponding latch to counter-clockwise position, so that when the solenoid swings the bail inwardly or counter-clockwise, as seen in Fig. 11, the latch engages the notch and in its corresponding plunger and said plunger is carried forward to engage its sector with the tilt bar. In this instance each plunger may carry at its inner end and extending downwardly from it a block of insulating material till, the inner face of which engages the turned-down end of a. spring ace secured to each latch. In this case, the

switch 23 may be arranged ightly diflc fi fly. the movable contact- Zhz being mounted on a bar 22!: pivoted at opposite ends and normally extending vertically downward behind the plungers. so that movement of a plunger rotates it counterclockwise in Fig. 11 to close switch 22.

Referring now more particularly to Figs. 12 and 13, there are shown still further simplified forms of apparatus in which the operation of the push buttons is manual, the solenoid, bail and latches all being eliminated and the necessary force required to operate the tuner being applied by the user in pushing the buttons.

The adjustment of the sectors, both as to the means for clamping them in position and the manner of adjusting them, is the same as already described with reference to fig. 10 and the clutch mechanism is substantially the same as that already described, wlth the single exception that since the solenoid driven ball is no longer present, the clutch engagement and dis-engagement lever M2 is now pivotally connected to a bail 280 pivoted as at 26! and having the operating rod 2|! pivotally attached as at iii. The ball extends across the path of motion of all of the plungers so that on pushing any push button, the bail 260 is engaged by the depressed plunger and rotated counter-clockwise as in Fig. 13, thereby declutching the condenser shaft from gear l1 and permitting easier operation of the button.

Since the power for' moving the tuner is applied by the finger of the operator, the plungers in this instance extend forward and terminate in the push buttons instead of just back of the bail 26 as in the forms previously described.

While I have shown and described certain preferred embodiments of my invention, it will be understood that modifications and changes may be made, without departing from the scope of my invention, as will be clear to those skilled in the I claim:

1. In push button tuning mechanism, in combination, a tilt bar, tuning means connecmd thereto to be driven thereby. a plurality of plungers for selectively operating said tilt bar, each of said plungers having a sector rotatably mounted thereon for engaging said tilt bar and determining the angular position thereof, a plurality of push buttons each corresponding to a plunger, said push buttons being arranged to be pushed inwardly and pulled outwardly from neutral position, and means operatively connecting each push button with the sector on its corresponding plunger for rotation when said button is outwardly displaced from neutral, whereby each push button may be preset without the use of tools.

2. In push button tuning mechanism, in combination, a tilt bar. tuning means connected thereto to be driven thereby, a plurality of plungers for selectively operating said tilt bar, each of said plungers having a sector rotatably mounted thereon for engaging said tilt bar, a plurality of push buttons, each corresponding to a. plunger, a worm mounted on each plunger and engaging the corresponding sector for rotation thereof, a shaft for driving each worm and means for connecting each push button to its corresponding shaft for rotation thereof, whereby rotation of said push button may rotate its corresponding sector.

3. In push button tuning mechanism, in combination, a tilt bar, tuning means connected thereto to be driven thereby, a plurality of plungers for selectively operating said tilt bar. each of said plungers having a sector rotatably mounted thereon for engaging said tilt bar, a worm engaging each oi said sectors for adjusting and holding the'same in adjusted position, a shaft extending from each worm into its corresponding push button, but normally disengaged for rotation, said shaft and said push button being arranged to be engaged for rotation together on outward displacement of said push button.

4. In push button tuning mechanism, in combination, a tilt bar, tuning means connected thereto to be driven thereby, a plurality of plungers for selectively operating said tilt bar, each of said plungers having a sector rotatably mounted thereon for engaging said tilt bar, a worm engaging each of said sectors for adjusting and holding the same in adjusted position, a shalt extending from each worm into its corresponding push button, but normally disengaged therefrom for rotation, a spline on the end of said shaft, and an internal spline on the inner end of said push button, whereby pulling said push button outwardly engages said splines for rotation of said shaft by said push button.

HAROLD J. McGARVEY. 

